Various embodiments of encapsulated aftertreatment systems for exhaust gases in particular of internal combustion engines of motor vehicles, especially utility vehicles have been disclosed. The disclosure includes exhaust gas aftertreatment units combined to a single unit within a case having joint supply connections on the case side for these exhaust gas aftertreatment units which in turn are at least partially designed encapsulated within the unit. This does not only result in considerable construction expenses for the system and a relatively large space requirement. In fact, the adjustment to different cases of application, such as the adjustment to internal combustion engines of different sizes with different volume flows flowing through the exhaust gas aftertreatment system also requires separately set up aftertreatment systems with units combined within the latter and designed accordingly.
Said encapsulated aftertreatment system has been disclosed for example in DE 102 50 050 A1. In it, in part separate enclosures are again provided and required within the aftertreatment system encapsulated with a separate case having supply connections on the case side for the exhaust gas aftertreatment units combined in the unit to achieve the flow through the exhaust gas aftertreatment units in the desired order.
The supply connection on the flow side with the supply connections arranged axially opposite from each other leads into an inflow chamber, from which the flow is directed at a downstream, ring-shaped particle filter designed for radial flow-through via oxidation catalysts designed for axial flow-through. From the particle filter, the exhaust gas flows onto a central collection pipe radially on the inside, onto which urea is injected and which retains a hydrolysis catalyst, if applicable. The collection pipe leads into a redirection chamber from which the flow through the SCR catalysts arranged around the collection pipe occurs converse to the collection pipe, said SCR catalysts leading into a ring-shaped redirection area adjacent to the particle filter separated from the particle filter. From said redirection area, the exhaust gas flows into a ring-shaped area interspersed with SCR catalysts surrounding the collection pipe. The ring-shaped area is connected with the supply connection axially opposite the supply connection on the exhaust gas side and, relative to the case encapsulating the system, to the supply connection on the flow side.
Another embodiment of an encapsulated exhaust gas aftertreatment system has been disclosed in U.S. Pat. No. 3,996,016 A. As implied in the preamble of claim 1, said exhaust gas aftertreatment system has a modular design with disk-shaped assemblies. The exhaust gas aftertreatment units are designed in ring shape and are arranged encircling a central supply channel in axial succession and axially separated from each other. The ring-shaped exhaust gas aftertreatment units are radially traversed starting from this supply channel and are enclosed by a ring-shaped collection channel radially on the outside. Said collection channel leads to a connecting space arranged coaxially in extension of the supply channel and is connected to an outflow pipe via the latter; said outflow pipe running in axial extension of the supply channel.
With said modular design of the exhaust gas aftertreatment system consisting of disk-shaped assemblies traversed in the direction of the disk plane and connected consecutively with each other diagonally to the disk plane, the stringing together of the modules creates the condition for designing an exhaust gas system that matches the number of cylinders of the internal combustion engine for different conversion rates and exhaust gas back pressures. This is also possible with the number of assemblies combined into modules of the exhaust gas aftertreatment system alone, without making any changes to the design of said assemblies and at least without making basic changes to the combination of the assemblies to create the exhaust gas aftertreatment system.
Another design of an exhaust gas aftertreatment system has been disclosed in DE 20 2007 004 230 U1. In it, exhaust gas aftertreatment units of different functions arranged in succession in an axial direction and axially traversed are provided. They are supported by means of support rings in a common case at a stable position to each other. The common pipe-shaped case consists of the pipe sections arranged in succession in an axial direction corresponding to the exhaust gas aftertreatment units. Said pipe sections retain one of the exhaust gas aftertreatment units each and their axially opposed buffer areas are surrounded by strap retainers and they are connected to the system in a stable and sealing position by means of said strap retainers.